Armature-torsion spring suspension assembly



March $1970 "GH JJH E Q JR; 'ETAL [3,493,308

ARMATUREJ RS ION SPRING SUSPENSION ASSEMBLY- Filed Sept. 5, 1968 12 Sheets-Sheet 1 2 l l'l/ -'r 3 il INVENTORS. GEORGE T. MILLER,JR. MARION L. GEORGE BY ROY MILLER ATTORNEY.

Margh 3, .1970 G. T. MILLERHJR. ET AL ARMATURE-TORSION SPRING SUSPENSION ASSEMBLY Filed Sept. 5, 1968 I 2 Sheets-Sheet 2 INPUT TORQUE COIL LEADOUTS \7 EA. POSITIVE SOLENOIDAL ans (4 BITS OPPOSITE ENDS) POLETIPS 1 1 a A MOST SIGNIFICANT BIT. NEGATIVE INPUT '6 l I I FIXED INLET I ORIFICE POWER STAGE SPOOL United States Patent O 3,498,308 ARMATURE-TORSION SPRING SUSPENSION ASSEMBLY George T. Miller, Jr., Granada Hills, and M21101]. L.

George, Studio City, Calif., assignors to the United States of America as represented by the Secretary of the Navy Filed Sept. 5, 1968, Ser. No. 757,589 Int. Cl. GlJSd 7/06; G08c 9/04; F16k 31/08 U.S. Cl. 13785 4 Claims ABSTRACT OF THE DISCLOSURE A rotor-suspension assembly for a servovalve which converts digital word value input commands to analog hydraulic power outputs. A torsionally supported armature for operating a conventional flapper valve is driven by an array of solenoid torquers which receive parallel word command voltages. The voltages are applied in a *-7 bit, twos complement, parallel binary input mode, enabling the generation of all Word values inclusive to $127.

BACKGROUND OF THE INVENTION In a prior art digital computer controlled shipboard missile launcher, the positioning of the launcher was attained by use of an analog servovalve which required a digital-to-analog converter and an associated current amplifier. Recent eflort has been directed toward the substitution of a digital servovalve, operated by the digital computer, which eliminates the necessity for the analog converter and current amplifier.

SUMMARY OF THE INVENTION In the present invention, a flapper valve, which is connected to an oscillatable armature, and a power stage spool, controlled by the flapper valve, may be of conventional construction, the armature, however, differing in its construction, together with the substitution of an array of digital solenoidal torquers which operates at magnetic saturation, thus providing a stable flow vs. word value characteristic which is independent of input voltage variations (near nominal voltage). The torquers are substantially identical and are operated at the same voltage, their eflective forces being attained by sizing the pole tip areas in a binary manner. The armature is suspended by torsion tubes, the bores of which may be conveniently reamed to larger size, without disassembly of the apparatus, to thus change their spring rates.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevation of the subject of the invention, the torquers being omitted.

FIG. 2 is an end elevation as viewed in the direction of arrow 2, FIG. 1,

FIG. 3 is a section taken on lines 33, FIG. 1, and

FIG. 4 is an operational schematic of the entire digital servovalve.

DESCRIPTION OF THE PREFERRED EMBODIMENT Armature 10 comprises a non-magnetic bar 12, journaled to valve body 13 by a pair of tubes 14, the ends of each of which are rigidly aflixed to the bar 12 and valve body 13 and which may twist about axis A. Nozzle flapper valve 16 is rigidly atfixed to bar 12 and moves relative to a pair of conventional nozzles, its lower end being formed as a feed back spring 18 which engages a power stage spool valve. The hydraulic amplifier, spool valve and associated parts are all of conventional construction and hence not shown.

Each cruciform arrangement is provided with a bore 24 through which a reamer may be inserted to enlarge the bores of tubes 14 and thus change their spring rates to thus suitably calibrate the apparatus for desired mode of operation.

Each end of bar -12 is provided with four integral arms 20, disposed in a cruciform arrangement, to each of which is a-fiixed a pole tip 22 of magnetic material. As will be apparent from FIG. 2, the areas of the pole tips differ, their areas varying in a binary manner, whereby the various forces F F etc. will vary in a binary manner.

Eight solenoidal torques (shown in FIG. 4) associated with respective pole pieces 22 receive parallel word command voltages. The electronically switched step voltages are applied to the valve in ai7 bit, twos complement, parallel binary input mode enabling the generation of all words inclusive to $127. The digital solenoidal torquer is mechanized with seven positive digits and a single negative most significant digit (M.S.D.) each producing a binary weighted torque. In generating negative outputs the negative M.S.D. is always energized and the negative torque output T is reduced by the summation of positive torque outputs.

The invention described herein may be manufactured and used by or for the government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is: 1. In an electro-hydraulic servo device of the type having a valve adapted to be positioned to produce proportional fluid flow, a flapper valve type hydraulic amplifier for controlling the position of the valve, and an armature aflixed to the flapper valve for controlling the hydraulic amplifier, the improvements, in combination, wherein said armature comprises:

a member supported by torsional pivot means for limited rotary oscillation about a predetermined axis,

said member having at least one set of angularly spaced arms emanating radially from said axis for applying torque thereto,

a magnetic pole tip aflixed to the end of each arm,

a solenoid torquer disposed adjacent each pole tip for applying a saturated magnetic force thereto,

the pole tip areas being sized to produce various forces in a binary relationship.

2. Apparatus in accordance with claim 1 wherein:

the flapper valve is afiixed to said member midway of its length, and

the ends of same are each provided with a set of arms,

each set comprising four,

the construction and arrangement being such that the torquers apply seven word values corresponding to seven positive digits and one most significant negative digit, whereby various combinations of energization of the solenoids in a parallel binary input mode are eflective to produce force values in increments of 1, between :127, inclusive.

3. Apparatus in accordance with claim 1 wherein, said torsional pivot means comprises at least one torsion tube disposed concentric with said axis, an end of said tube being accessible for enlarging its bore to thereby vary its torsional spring constant.

4. Apparatus in accordance with claim 1 wherein: said flapper valve is aflixed to said member at the midpoint of its length and the ends of same are each provided with a set of arms,

said torsional pivot means comprising a pair of tubes,

one disposed on each side of said midpoint,

each set of arms having an access aperture, concentric with said axis, through which means may be inserted to enlarge the bore of each tube to thereby vary its 3,315,103 4/1967 Duff et a1. 340-347 XR torsional spring constant.

ROBERT G. NILSON, Primary Examiner References Cited UNITED STATES PATENTS 5 US. Cl. X.R. 3,225,346 12/1965 Buddenhagen 137-82 XR 137--625.64; 340-347 

